GEM System Research Articles

Analysis of Data Recorded by a Large Prototype TPC Equipped with a Two Layer GEM System

Abstract A TPC is considered as tracking detector at a future linear collider. The LCTPC (Linear Collider TPC) collaboration has therefore constructed a prototype TPC for R&D purposes. MPGD readout structures, such as Micromegas or GEMs, are being considered for the TPC since the demands on space and momentum resolution can not be met with a traditional wire based readout. The prototype TPC is placed in a 1 Tesla magnet at DESY and tested using an electron beam. Analyses of data taken during two different measurement series, in 2009 and 2010, are presented here. The TPC was instrumented with a two layer GEM system and read out using modified electronics from the ALICE experiment, including the programmable charge sensitive preamp-shaper PCA16. The PCA16 chip has a number of programmable parameters which allows studies to determine the settings optimal to the final TPC. Here, the impact of the shaping time on the space resolution in the drift direction was studied. It was found that a shaping time of 60 ns is the best setting (of the available choices) for a sampling frequency of 20 MHz. In addition, the resolution in the bend plane was studied. Unfortunately, the measurements suffered from distortions in the electric field close to the readout, which deformed the track projections and had to be corrected for. This was done using the Millipede method. The final results obtained are a resolution of 59.1 ± 0.4 μm in the bend plane and 204 ± 9 μm in the drift direction, both extrapolated to zero drift distance. The measured values are consistent with the final goal of the ILD.

186 POSTER Screening for the inhibitor against filopodia protrusion

Traditional modeling methods using rate equations and enzyme kinetics aloneare insufficient for large-scale plant modeling. As the development of methods to address the challenges posed by plant systems biology is a priority, plant systems biology should take advantage of current modeling strategies and advances in system-wide analysis that have been developed in efforts to achieve both unicellular and multi-cellular modeling.There are currently two large-scale modeling projects undertaken by E-Cell:e2coli, which aims to simulate the E. coli bacterium, and e-Rice, which aims at simulating the rice plant. e-Rice is one of the first attempts to simulate a whole plant organism. Our preliminary goal is to create a generic model for the basic metabolism in a plant cell that can then be adapted to cells residing at different sites in a rice plant. The current version of the basic model consists of reactions that take place in the chloroplast, mitochondrion, peroxisome, and cytosol.The reconstruction of even a prokaryotic cell poses many challenges.3, 20, 21With plants, a huge amount of data and many data types are involved, complicating the process even further.22–24 Even in the same genome, these data vary depending on the type of organelles, cells, tissues, and organs involving multiple development phases. However, by obtaining cell-wide data at two different levels—the genome for global properties and the metabolome for expressed physical properties, a basic dataset for cell simulation can be prepared for computer simulations. Our endeavor to simulate a whole plant is still in its initial stages where we are developing the tools and algorithms necessary for integrating vast amounts of available data and information. The tools and algorithms being developed are indispensable for reliable and comprehensive large-scale simulations, and can be adapted to various organisms including plants and mammals.In summary, our integrative approach and methods addresses large-scale modeling that is being developed at the Institute for Advanced Biosciences. Our approach for constructing the cell model consists of using 1) the Genome to E-Cell System (GEM System) for modeling pathways based on genomic information, 2) rice metabolome research using capillary electrophoresis mass spectrometry (CE-MS), 3) Atomic Reconstruction of Metabolism (ARM), and 4) the hybrid static/dynamic algorithm for integrating static models based on pathway stoichiometry and dynamic models using kinetics. These applications provide a systematic method for acquiring and integrating various data types for whole cell modeling using the E-Cell simulation environment.

TOWARD A MONITORING AND FORECASTING SYSTEM FOR ATMOSPHERIC COMPOSITION

The Global and Regional Earth System Monitoring Using Satellite and In Situ Data (GEMS) project is combining the manifold expertise in atmospheric composition research and numerical weather prediction of 32 European institutes to build a comprehensive monitoring and forecasting system for greenhouse gases, reactive gases, aerosol, and regional air quality. The project is funded by the European Commission as part of the Global Monitoring of Environment and Security (GMES) framework. GEMS has extended the data assimilation system of the European Centre for Medium-Range Weather Forecasts (ECMWF) to include various tracers for which satellite observations exist. A chemical transport model has been coupled to this system to account for the atmospheric chemistry. The GEMS system provides lateral boundary conditions for a set of 10 regional air quality forecast models and global atmospheric fields for use in surface flux inversions for the greenhouse gases. Observations from both in situ and satellite sources are used as input, and the output products will serve users such as policy makers, environmental agencies, the science community, and providers of end-user services for air quality and health. This article provides an overview of GEMS and uses some recent results to illustrate the current status of the project. It is expected that GEMS will grow into a full operational service for the atmospheric component of GMES in the next decade. Part of this transition will be the merge with the Protocol Monitoring for the GMES Service Element: Atmosphere (PROMOTE) GMES project into the Monitoring of Atmospheric Composition and Climate (MACC) project.

Readout of TPC tracking chambers with GEMs and pixel chip

Two layers of GEMs and the ATLAS Pixel Chip, FEI3, have been combined and tested as a prototype for Time Projection Chamber (TPC) readout at the International Linear Collider (ILC). The double-layer GEM system amplifies charge with gain sufficient to detect all track ionization. The suitability of three gas mixtures for this application was investigated, and gain measurements are presented. A large sample of cosmic ray tracks was reconstructed in 3D by using the simultaneous timing and 2D spatial information from the pixel chip. The chip provides pixel charge measurement as well as timing. These results demonstrate that a double GEM and pixel combination, with a suitably modified pixel ASIC, could meet the stringent readout requirements of the ILC.

Development of a new high sensitivity potassium magnetometer for geophysical mapping

Ivan Hrvoic, Mike Wilson, and Francisco Lopez* of Canadian company GEM Systems** review the available range of magnetometers used for various geophysical applications finding special benefits from the potassium version it has developed.

The readout of a GEM or Micromegas-equipped TPC by means of the Medipix2 CMOS sensor as direct anode

We have applied the Medipix2 pixel CMOS chip as direct anode readout for a TPC. For the gas amplification two options have been investigated: (i) a three-stage GEM system and (ii) a Micromegas mesh. The structure of the cloud of primary electrons, left after interactions of 55Fe quanta with the gas is visible with unprecedented precision. This proof-of-principle is an essential step in our project to realize a monolithic pixel sensor with integrated Micromegas, to be developed specially for the readout of TPCs, and applicable for drift chambers in general.

The readout of a GEM or Micromegas-equipped TPC by means of the Medipix2 CMOS sensor as direct anode

We have applied the Medipix2 pixel CMOS chip as direct anode readout for a TPC. For the gas amplification two options have been investigated: (i) a three-stage GEM system and (ii) a Micromegas mesh. The structure of the cloud of primary electrons, left after interactions of 55 Fe quanta with the gas is visible with unprecedented precision. This proof-of-principle is an essential step in our project to realize a monolithic pixel sensor with integrated Micromegas, to be developed specially for the readout of TPCs, and applicable for drift chambers in general.

GE specialty materials completes Osmonics deal

Traditional modeling methods using rate equations and enzyme kinetics aloneare insufficient for large-scale plant modeling. As the development of methods to address the challenges posed by plant systems biology is a priority, plant systems biology should take advantage of current modeling strategies and advances in system-wide analysis that have been developed in efforts to achieve both unicellular and multi-cellular modeling.There are currently two large-scale modeling projects undertaken by E-Cell:e2coli, which aims to simulate the E. coli bacterium, and e-Rice, which aims at simulating the rice plant. e-Rice is one of the first attempts to simulate a whole plant organism. Our preliminary goal is to create a generic model for the basic metabolism in a plant cell that can then be adapted to cells residing at different sites in a rice plant. The current version of the basic model consists of reactions that take place in the chloroplast, mitochondrion, peroxisome, and cytosol.The reconstruction of even a prokaryotic cell poses many challenges.3, 20, 21With plants, a huge amount of data and many data types are involved, complicating the process even further.22–24 Even in the same genome, these data vary depending on the type of organelles, cells, tissues, and organs involving multiple development phases. However, by obtaining cell-wide data at two different levels—the genome for global properties and the metabolome for expressed physical properties, a basic dataset for cell simulation can be prepared for computer simulations. Our endeavor to simulate a whole plant is still in its initial stages where we are developing the tools and algorithms necessary for integrating vast amounts of available data and information. The tools and algorithms being developed are indispensable for reliable and comprehensive large-scale simulations, and can be adapted to various organisms including plants and mammals.In summary, our integrative approach and methods addresses large-scale modeling that is being developed at the Institute for Advanced Biosciences. Our approach for constructing the cell model consists of using 1) the Genome to E-Cell System (GEM System) for modeling pathways based on genomic information, 2) rice metabolome research using capillary electrophoresis mass spectrometry (CE-MS), 3) Atomic Reconstruction of Metabolism (ARM), and 4) the hybrid static/dynamic algorithm for integrating static models based on pathway stoichiometry and dynamic models using kinetics. These applications provide a systematic method for acquiring and integrating various data types for whole cell modeling using the E-Cell simulation environment.

Automatic Generation of Cell-Wide Pathway Model from Complete Genome

Knowledge in molecular biology is rapidly accumulating in the fields of genome, transcriptome, proteome, and metabolome, demanding for a systems biology approach in order to view the dynamic behavior of a cell as a complex system. However, simulation is a challenging task especially where large-scale modeling is required due to the necessity for vast amount of accurate parameters. E-Cell project [2] estimated the necessary cost for modeling the whole cell of Escherichia coli to be at least 1800 man month, from the experience in modeling an in silico mitochondria. Therefore a large scale modeling of cell in silico demands for a novel high-throughput approach. If successfully integrated, availability of large amount of genome sequence, transcripts and expression data, enzyme reaction data, metabolic pathway maps, and the data of metabolites in cells will create a strong base for a qualitative cell model. The Genome-based E-cell Modeling System (GEM System) developed upon the generic bioinformatics workbench G-language Genome Analysis Environment [1] realizes a fully automatic conversion of genome sequence data into a qualitative in silico cell model, linking information from major public databas such as GenBank, EMBL, SWISS-PROT, KEGG, ARM, Brend, and WIT.

Is the Algol‐type Eclipsing Binary RX Geminorum a True Triple System?

ABSTRACTAn analysis of the times of minimum light for the long‐period Algol‐type eclipsing binary RX Gem is presented based on a new linear ephemeris. The O - C curve shows a cyclic oscillation with a period of 55.7 yr and a semiamplitude of 0.0645 day. Assuming the change to be due to the presence of a “third body” revolving around the RX Gem system, the parameters of the third body’s orbit are derived. Since the third‐body assumption is in good agreement with the spectroscopic data from several authors and with published photometric solutions (Gaposchkin, Hall, & Walter; Giuricin et al.), RX Gem is likely to be a triple system. In this case, the third body is an A‐type star in a circular orbit, which is nearly coplanar to the orbit of the eclipsing pair. However, the recent light‐curve analysis by Olson & Etzel does not show any third light, so the third star (M3>2.41 M⊙) may be an unseen neutron star or black hole. Additional eclipse timings over the next decade will be important to verify the presence of the third body.

The Underlying White Dwarf Accretor in the Dwarf Nova UU Aquilae

ABSTRACTWe present a high‐gravity, solar composition model atmosphere and model accretion disk study of the U Gem type dwarf nova UU Aql. We have identified the far‐UV signature of the underlying white dwarf for the first time. Our best‐fit model atmosphere to the observed far‐UV spectrum in quiescence is 27,000 ± 1000 K. The solar abundance high‐gravity photosphere provides a consistent explanation for the sharp absorption lines due to metals in the white dwarf’s atmosphere. This interpretation is also consistent with the predicted 20,000–30,000 K small, hot, far‐UV source (smaller than an accretion disk) proposed by Patterson & Raymond. Model accretion disk fits do not account for the sharp absorption lines and continuum slope. The best‐fit accretion disk corresponds to Mwd = 0.8 M⊙, i = 60°, and M ˙ = 10-9.5 M⊙ yr−1. Optically thick disk models at accretion rates lower than 1 × 10-9.5 M⊙ yr−1 are ruled out because of marked flux deficiency shortward of 1400 Å. Theoretical arguments are presented that rule out accretion rates as high as 1 × 10-9.5 M⊙ yr−1 during dwarf nova quiescence. While we can rule out the quiescent disk as being a significant UV flux contributor, we believe the heated white dwarf accounts for the majority of the far‐UV flux. The white dwarf is only the fifth accretor among U Gem systems with a known surface temperature. The temperatures of all five accretors lie between 25,000 and 35,000 K.

A componentized architecture for dynamic electronic markets

The emergence and growing popularity of Internet-based electronic market-places, in their various forms, has raised the challenge to explore genericity in market design. In this paper we present a domain-specific software architecture that delineates the abstract components of a generic market and specifies control and data-flow constraints between them, and a framework that allows convenient pluggability of components that implement specific market policies. The framework was realized in the GEM system. GEM provides infrastructure services that allow market designers to focus solely on market-issues. In addition, it allows dynamic (re)configuration of components. This functionality can be used to change market-policies as the environment or market trends change, adding another level of flexibility to market designers and administrators.

THE ENIGMATIC STAR EZ PEGASI - A MYSTERY SOLVED ?

ABSTRACT EZ Peg, a ninth-magnitude G star that has been classified by various authors as an irregular variable, a U Gem system, and a contact binary is shown to have all the spectroscopic and photometric characteristics of an active-chromosphere RS CVn binary. The authors suggest that the reported "outburst" of 1943, when the spectrum appeared to be that of a B star, never occurred. The strong Ca II H and K reversals, viewed with low spectral resolution, caused the photospheric Ca II absorption to appear abnormally weak, mimicking a much earlier spectral type.

An overview of the Yale Gem system

AbstractThe Gem system is an experimental computing facility that provides low cost, high speed, graphics‐oriented computing to between ten and sixteen simultaneous users. It provides many unusual facilities to its users and presents a user interface that is unique in its convenience and flexibility. The motivation for the system, its design and user experience are described. Possible future avenues of research are also outlined.

SPECTRA OF THE M DWARF COMPANION IN U GEMINORUM.

ABSTRACT Spectroscopic scans of the U Gem system in the red and near-IR are reported. A composite spectrum is plotted which reveals that the secondary star in U Gem is an M dwarf whose spectrum contains a strong CaH feature at 6385 A and at least three TiO bands. The best estimate of the secondary's spectral type is shown to be dM4.5 with a probable error of about half a spectral class. The emission-line behavior of the U Gem system is briefly discussed.

U Geminorum-Type Stars

The light variations, properties of U Gem binary systems, outbursts of U Gem systems, and evolution and related problems are discussed.Recent high-speed photometry of Z Cha is mentioned in an addendum.

Binary Stars among Cataclysmic Variables. III. Ten Old Novae.

view Abstract Citations (247) References (37) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Binary Stars among Cataclysmic Variables. III. Ten Old Novae. Kraft, Robert P. Abstract ome of the spectroscopic and photometric properties of ten old novae of the spring, summer, and y autumn shy are considered. To the four binaries previously known (T CrB, DQ Her, T Aur, WZ ) are added GK Per (1901), V603 Aql (1918), and V1017 Sgr (1901, 1919). Orbits are given for the two of these three; the last is judged a binary from its composite spectrum. Two other novae, which e unusually narrow emission lines and show no certain velocity variations at the dispersions , are shown very probably to be pole-on objects. Since seven of the ten objects studied are certainly binaries, the hypothesis is advanced that member- in a certain type of close-binary system is a necessary condition for a star to become a nova. A binary el similar to that advanced earlier to explain the U Gem systems (Kraft 1962) is invoked for novae; te difficulties with its application to the case of VZ Sge are cited. A relationship, having a width of about + 1.5 mag., is shown to exist between the absolute magnitude he red component (at minimum h.ght) and the orbital period, in the sense that the brighter is the imal magnitude of the red star, the longer is the period. `ith decreasing period comes increasing tness of the red star relative to the blue. There is a tendency for the masses of novae to increase with easing period and higher luminosity. The masses so far found for novae range from 0.1 to 3 , and the luminosities from +10 ainter to 1. Any universal mechanism advanced to explain the outbursts of novae cannot depend mgly on mass or position in the HR diagram. [t is concluded that novae can belong to any population of stars, provided that population contains te close binaries of the appropriate hind. Most of them will therefore be found in stellar populations taining many binaries, such as the galactic disk, but their occasional presence in Type II systems is inctly possible. It is suggested that the frequency of novae per unit mass in a stellar system is a sure of angular momentum within that system. Publication: The Astrophysical Journal Pub Date: February 1964 DOI: 10.1086/147776 Bibcode: 1964ApJ...139..457K full text sources ADS | data products SIMBAD (23) Related Materials (11) Part 1: 1962ApJ...135..408K Part 2: 1962ApJ...136..312K Part 4: 1964ApJ...139..476M Part 5: 1964ApJ...140..921K Part 6: 1965ApJ...142.1041K Part 7: 1965ApJ...142.1588K Part 8: 1966ApJ...146..411M Part 9: 1967ApJS...15....1M Part 10: 1969ApJS...18..429M Part 11: 1969ApJ...158..589K Part 12: 1971ApJ...165..369M